<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .fu{
            display: flex;
            justify-content: center;
        }
        .zi{
            /*align-self:baseline;*/
            width: 40px;
            background-color: yellow;
            height: 100%;
        }
        .zi:nth-child(1){
            height: 300px;
        }
    </style>
</head>
<body>
<div class="fu">
    <div class="zi">1234</div>
    <div class="zi">456</div>
    <div class="zi">789</div>
</div>
</body>
</html>